The invention disclosed herein relates generally to mailing systems, and more particularly to a self-adjusting moistener system for moistening an envelope flap of an envelope being processed by the mailing machine.
Mailing systems, such as, for example, a mailing machine, often include different modules that automate the processes of producing mail pieces. The typical mailing machine includes a variety of different modules or sub-systems each of which performs a different task on the mail piece. The mail piece is conveyed downstream utilizing a transport mechanism, such as rollers or a belt, to each of the modules. Such modules could include, for example, a singulating module, i.e., separating a stack of mail pieces such that the mail pieces are conveyed one at a time along the transport path, a moistening/sealing module, i.e., wetting and closing the glued flap of an envelope, a weighing module, and a metering module, i.e., applying evidence of postage to the mail piece. The exact configuration of the mailing machine is, of course, particular to the needs of the user.
In the moistening/sealing module, a moistening device includes an apparatus for moistening the glue line on flaps of envelopes in preparation for sealing the envelopes in either a mailing machine or an inserter, and may also include a mechanism for moistening a tape. Moistening devices generally fall into two categories: contact and non-contact moistening systems. Contact systems generally deposit a moistening fluid, such as, for example, water or water with a biocide, onto the glue line on a flap of an envelope by contacting the glue line with a wetted applicator. Non-contact systems generally spray the moistening fluid onto the envelope flap.
In contact systems, the wetted applicator typically consists of a contact media such as a brush, foam or felt. The applicator is in physical contact with a wick. The wick is generally a woven material, such as, for example, felt, or can also be a foam material. At least a portion of the wick is located in a reservoir containing the moistening fluid. The moistening fluid is transferred from the wick to the applicator by physical contact pressure between the wick and applicator, thereby wetting the applicator. An envelope flap is guided between the wick and applicator, such that the applicator contacts the glue line on the flap of the envelope, thereby transferring the moistening fluid to the flap to activate the glue. The flap is then closed and sealed, such as, for example, by passing the closed envelope through a nip of a sealer roller to compress the envelope and flap together, and the envelope passed to the next module for continued processing.
There are problems, however, with conventional contact moistening systems. For example, in conventional contact moistening systems, it is difficult to accurately control the quantity of moistening fluid being transferred from the applicator to the envelope flap. If not enough moistening fluid is applied (xe2x80x9cunder-wettingxe2x80x9d), the envelope flap will not properly seal to the envelope body. If too much moistening fluid is applied (xe2x80x9cover-wettingxe2x80x9d), it can cause damage to the envelope and/or its contents. Excessive moistening can also negatively impact any printing performed on the envelope, such as, for example, a postage indicium. For example, if the printing is being done by an ink-jet printer, an excessive amount of moisture will cause the ink to run, thereby possibly rendering any printed information illegible.
There are several factors that contribute to the amount of moistening fluid deposited on the envelope flap. For example, the amount of moistening fluid deposited on the envelope is dependent upon the amount of moistening fluid in the reservoir. In many applications, the moistener fluid level varies over the entire range of the reservoir capacity (full to empty) before it is replenished. As the moistening fluid level decreases, the amount of moistening fluid deposited on the envelope flap also decreases. Testing has shown that approximately twice the amount of moistening fluid is deposited on an envelope when the reservoir is full as compared to when the reservoir is only one-eighth full for various wick materials. Testing has also indicated that a minimum amount of moistening fluid must be deposited on an envelope to adequately moisten the glue line of the envelope to ensure consistent sealing. When the reservoir is only one-eighth full, the amount of moistening fluid deposited on the envelope may not surpass this minimum amount, thereby resulting in low sealing rates. Attempts to correct this type of problem, such as, for example, by altering the wicking properties of the wick such that even when the level of fluid in the reservoir is low, the amount of moistening fluid wicked to the applicator is still sufficient to adequately moisten the envelope flap, have resulted in over-wetting conditions when the reservoir is full. This type of correction is, of course, unacceptable. Another factor that contributes to the amount of moistening fluid deposited on the envelope flap is the amount of moistening fluid transferred from the wick to the applicator. If more moistening fluid is transferred from the wick to the applicator, there will be more moistening fluid deposited on the envelope flap. The amount of moistening fluid transferred from the wick to the applicator is dependent, at least in part, on the amount of force acting between the applicator and the wick, i.e., the contact pressure between the applicator and wick. If too much pressure is applied, especially when the reservoir is full, an over-wetting condition can result. If not enough pressure is applied, especially when the reservoir is not full, an under-wetting condition can result.
Thus, there exists a need for a moistening system that can better control the distribution of moistening fluid on an envelope flap.
The present invention alleviates the problems associated with the prior art and provides a system and method to better control the distribution of moistening fluid on an envelope flap. The present invention provides a self-adjusting moistening system that compensates for a decrease in the amount of moistening fluid contained in the reservoir by automatically increasing the normal force between the applicator and wick as the moistening fluid level in the reservoir decreases. The self-adjusting system of the present invention provides better control over the amount of moistening fluid deposited on an envelope flap, thereby ensuring more consistent sealing, while also reducing the likelihood of an over-wetting condition when the reservoir is full.
In accordance with the present invention, the applicator is coupled to a float mechanism by a spring. The float mechanism is placed in the reservoir of moistening fluid. When the reservoir is full of moistening fluid, the spring is compressed, and therefore does not provide any force on the applicator. As the level of moistening fluid decreases, the height of the float mechanism in the reservoir will also decrease, thereby causing the spring to elongate. As the spring elongates, it will pull down on the applicator, thereby causing an increase in the force applied between the applicator and the wick. Accordingly, as the level of fluid decreases in the reservoir, the amount of force between the applicator and the wick, and therefore the amount of force applied between the applicator and envelope flap, proportionally increases. The proportional increase in force between the applicator and wick as the moistening fluid level decreases provides a more uniform deposition of the moistening fluid to the envelope flap as the level of the moistening fluid in the reservoir varies from full to empty.
Therefore, it should now be apparent that the invention substantially achieves all the above aspects and advantages. Additional aspects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. Moreover, the aspects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.